共查询到20条相似文献,搜索用时 31 毫秒
1.
G. A. Komandin V. I. Torgashev A. A. Volkov O. E. Porodinkov I. E. Spektor V. M. Mukhortov 《Physics of the Solid State》2010,52(9):1842-1849
Transmission and reflection spectra of Bi0.98Nd0.02FeO3.00 multiferroic thin films on MgO single-crystal substrates have been measured using submillimeter spectroscopy (on a backward-wave
tube spectrometer) and Fourier-transform infrared spectroscopy in the frequency range from 8 to 1000 cm−1 at room temperature. The complex permittivity spectra of the films have been calculated in terms of the layered medium model.
It has been revealed that a decrease in the film thickness leads to a considerable increase in the losses in a range of 30
cm−1 and the corresponding fivefold increase in the static permittivity (to 500 for a film 32 nm thick). This phenomenon has been
discussed in the framework of the phenomenological theory of phase transitions. 相似文献
2.
E. I. Nedrigaylov V. V. Styrov 《Bulletin of the Russian Academy of Sciences: Physics》2008,72(7):899-901
It is shown that the CO + O2 → CO2 catalytic reaction on the surface of Y2O3-Eu may lead to electronic excitation of Eu3+ luminescence centers due to the chemical energy release. The luminescence observed allows one to study the interaction between
molecular particles of ultralow (thermal) energies with surface by optical methods. 相似文献
3.
Tingyin Ning Cong Chen Yueliang Zhou Heng Lu Dongxiang Zhang Hai Ming Guozhen Yang 《Applied Physics A: Materials Science & Processing》2009,94(3):567-570
CaCu3Ti4O12 (CCTO) thin films were successfully prepared on LaAlO3 substrates by pulsed laser deposition technique. We measured the nonlinear optical susceptibility of the thin films using
Z-scan method at a wavelength of 532 nm with pulse durations of 25 ps and 7 ns. The large values of the third-order nonlinear
optical susceptibility, χ
(3), of the CCTO film were obtained to be 2.79×10−8 esu and 3.30×10−6 esu in picosecond and nanosecond time regimes, respectively, which are among the best results of some representative nonlinear
optical materials. The origin of optical nonlinearity of CCTO films was discussed. The results indicate that the CCTO films
on LaAlO3 substrates are promising candidate materials for applications in nonlinear optical devices. 相似文献
4.
Pb(Zr0.52Ti0.48)O3 (PZT)/LaNiO3 (LNO) thin films with highly (100) out of plane orientation were produced on SiO2/Si(100) and alkaline earth aluminosilicate glass substrates by pulsed laser deposition (PLD). Orientations of both PZT and
LNO films were evaluated using X-ray diffraction. The pure (100)-oriented PZT/LNO films were obtained under optimized deposition
conditions. Time of flight-secondary ion mass spectrometry analysis showed that LNO could effectively block interdiffusion
between the PZT films and the substrates. Fairly smooth surfaces of the PZT films with roughness of about 4 nm were observed
using an atomic force microscope. Cross sectional examination revealed that the films grew in columnar grains. The PZT films
grown on both SiO2/Si and glass substrates demonstrated very good ferroelectric characteristic at room temperature with remnant polarization
of up to 26 μC/cm2.
PACS 79.20.DS; 77.84.DY; 78.70.Ck 相似文献
5.
X.T. Li P.Y. Du H. Ye C.L. Mak K.H. Wong 《Applied Physics A: Materials Science & Processing》2008,92(2):397-400
Textured LixNi2-xO (LNO) thin films have been fabricated on (001)MgO substrates by pulsed laser deposition technique. The as-deposited LNO
films shows a conductivity of 2.5×10-3 Ω m and possess a transmittance of about 35% in the visible region. Subsequent deposition of Sr0.6Ba0.4Nb2O6 (SBN60) thin film on these LNO-coated MgO substrates resulted in a textured SBN layer with a 〈001〉 orientation perpendicular
to the substrate plane. Phi scans on the (221) plane of the SBN layer indicated that the films have two in-plane orientations
with respect to the substrate. The SBN unit cells were rotated in the plane of the film by ± 8.2° as well as ± 45° with respect
to the LNO/MgO substrate. Besides the highly (00l)-orientation, the SBN films also exhibited a dense microstructure as shown
by scanning electron microscopy. The electro-optic coefficient (r33) of the SBN film was measured to be 186 pm/V. On the basis of our results, we have demonstrated that the LNO film can be
used as a buffer layer as well as a transparent bottom electrode for waveguide applications. The SBN/LNO heterostructure is
also a suitable candidate for integrated electro-optics devices.
PACS 42.79.Gn; 42.82.Et; 78.20.Ci 相似文献
6.
G.S. Wang X.J. Meng Z.Q. Lai J. Yu J.L. Sun S.L. Guo J.H. Chu 《Applied Physics A: Materials Science & Processing》2003,76(1):83-86
Ferroelectric Bi3.25La0.75Ti3O12 (BLT) thin films have been grown on Pt/Ti/SiO2/Si substrates by chemical solution methods. X-ray diffraction analysis shows that BLT thin films are polycrystalline with
(171)-preferential orientation. Atomic force microscopy investigation shows that they have large grains about 120 nm in size.
A Pt/BLT/Pt capacitor has been fabricated and showed excellent ferroelectricity, with a remnant polarization and coercive
field of 24 μC/cm2 and 116 kV/cm, respectively. The capacitor shows no polarization fatigue up to 109 switching cycles. The optical constants (n,k) of the BLT thin films in the wavelength range 0.35–1.7 μm were obtained by
spectroscopic ellipsometry measurements, and the band-gap energy was found to be about 3.25 eV.
Received: 16 October 2001 / Accepted: 6 January 2002 / Published online: 3 June 2002
RID="*"
ID="*"Corresponding author. Fax: +86-21/65830-734, E-mail: gswang@mail.sitp.ac.cn 相似文献
7.
Zhaoxia Bi Rong Zhang Weiping Li Xusheng Wang Shulin Gu Bo Shen Yi Shi Zhiguo Liu Youdou Zheng 《中国科学G辑(英文版)》2003,46(1):41-46
With the solid phase reaction between pulsed-laser-deposited (PLD) ZnO film and α-Al2O3 substrate, ZnAl2O4/α-Al2O3 complex substrates were synthesized. X-ray diffraction (XRD) spectra show that as the reaction proceeds, ZnAl2O4 changes from the initial (111)-oriented single crystal to poly-crystal, and then to inadequate (111) orientation. Corresponding
scanning electron microscope (SEM) images indicate that the surface morphology of ZnAl2O4 transforms from uniform islands to stick structures, and then to bulgy-line structures. In addition, XRD spectra present
that ZnAl2O4 prepared at low temperature is unstable at the environment of higher temperature. On the as-obtained ZnAl2O4/α-Al2O3 substrates, GaN films were grown without any nitride buffer using light-radiation heating low-pressure MOCVD (LRH-LP-MOCVD).
XRD spectra indicate that GaN film on this kind of complex substrate changes fromc-axis single crystal to poly-crystal as ZnAl2O4 layer is thickened. For the single crystal GaN, its full width at half maximum (FWHM) of X-ray rocking curve is 0.4°. Results
indicate that islands on thin ZnAl2O4 layer can promote nucleation at initial stage of GaN growth, which leads to the (0001)-oriented GaN film. 相似文献
8.
Photoacoustic spectroscopy (PAS) is one of the important branches of spectroscopy, which enables one to detect light-induced
heat production following the absorption of pulsed radiation by the sample. As2S3, As2Se3 and GeSe2 exhibit a wide variety of photo-induced phenomena that enable them to be used as optical imaging or storage medium and various
electronic devices, including electro-optic information storage devices and optical mass memories. Therefore, accurate measurement
of thermal properties of semiconducting films is necessary to study the memory density. The thermal conductivity of thin films
of As2S3 (thickness 100 μm and 80 μm), As2Se3 (thickness 100 μm and 80 μm) and GeSe2 (thickness 120 μm and 100 μm) has been measured using PAS technique. Our result shows that the thermal conductivity of thicker films is larger than the
thinner films. This can be explained by the thermal resistance effect between the film and the surface of the substrate.
相似文献
9.
Al<Subscript>2</Subscript>O<Subscript>3</Subscript> plasma production during pulsed laser deposition
F. Caridi L. Torrisi A. M. Mezzasalma G. Mondio A. Borrielli 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2009,54(2):467-472
A Nd:YAG laser operating in second harmonic (532 nm), 3 ns pulse duration, 150 mJ pulse energy, and 10 Hz repetition rate,
is employed to irradiate Al2O3 target placed in high vacuum. The produced plasma is investigated by an ion collector used in time-of-flight configuration
and by a mass quadrupole spectrometer, in order to determine the equivalent plasma temperature and the atomic and molecular
composition. Pulsed laser deposition technique has been used to produce thin films on different substrates placed close to
the target. Different surface analyses, such as energy dispersive X-ray fluorescence (EDXRF), X-ray photoelectron spectroscopy
(XPS) and surface profilometry are employed to characterize the produced films. Measurements of ablation yield, plasma equivalent
temperature, acceleration voltage and characterization of grown thin films are presented and discussed. 相似文献
10.
M. Kodu T. Avarmaa H. Mändar R. Jaaniso 《Applied Physics A: Materials Science & Processing》2008,93(3):801-805
This paper reports the first results obtained on monobarium gallate thin films grown on silicon and platinum coated substrates
by pulsed laser deposition. The influence of oxygen background pressure and substrate (or post-annealing) temperature on the
film properties was studied. The films were characterized by XRD, RHEED, AFM, photoelectron and electrical impedance spectroscopy.
The structure analysis showed that the films crystallized into a hexagonal phase, most probably into (metastable) α-BaGa2O4. Depending on deposition conditions, films with different (from nearly epitaxial to polycrystalline) textures were obtained. 相似文献
11.
Bi3.25Pr0.75Ti3O12 (BPT) ferroelectric thin films have been prepared by chemical solution deposition on platinized Si substrates. Well-crystallized BPT films can be achieved by 600 °C rapid thermal annealing. The film surface is smooth and crack-free, composed of uniform spherical grains around 90–100 nm in diameter. The electrical properties of Pt/BPT/Pt thin film capacitors were characterized by hysteresis and impedance measurements. The remanent polarization of 700 °C annealed BPT films is around 20 C/cm2 at 120-kV/cm stimulus field. The dielectric constant is around 380 at 10 kHz, 100-mV amplitude. The remanent polarization of BPT film showed a slight reduction, 10% of its original value, after 2.8×109 cycles, while a 30% reduction of non-volatile polarization was observed. PACS 81.15.-z; 77.55.+f; 77.22.Gm 相似文献
12.
Mingfu Zhang Hengzhi Chen Bin Yang Wenwu Cao 《Applied Physics A: Materials Science & Processing》2009,97(4):741-744
Layered-perovskite ferroelectric Bi2.85La0.15TiNbO9 (LBTN) optical waveguiding thin films were grown on fused silica substrates by pulsed laser deposition (PLD). X-ray diffraction
(XRD) revealed that the film is highly (00l) textured. We observed sharp and distinct transverse electric (TE) and transverse magnetic (TM) multimodes and measured the
refractive indices of LBTN thin films at 632.8 nm. The ordinary and extraordinary refractive indices were calculated to be
n
TE=2.358 and n
TM=2.464, respectively. The film homogeneity and the film-substrate interface were analyzed using an improved version of the
inverse Wentzel–Kramer–Brillouin (iWKB) method. The refractive index of the film remains constant at n
0 within the waveguiding layer. The average transmittance of the film is 70% in the wavelength range of 400–1400 nm and the
optical waveguiding properties were evaluated by the optical prism coupling method. Our results showed that the LBTN films
are very good electro-optical active material. 相似文献
13.
Jose Antonio Ayllon Monica Lira-Cantu 《Applied Physics A: Materials Science & Processing》2009,95(1):249-255
The effects of oxygen content in the sputtering gas on the crystallographic and optoelectronic properties of 210 nm-thick
Zr–doped In2O3 (Zr–In2O3) films by rf magnetron sputtering were initially studied. The results of X-ray diffraction show that the Zr–In2O3 films grown on glass substrates exhibit mixed crystallographic orientations. Moreover, the Zr–In2O3 film grown in an Ar atmosphere promotes the appearance of crystallographic orientation of (222). The surface of the Zr–In2O3 film becomes rougher as the oxygen content in the sputtering gas decreases; the current images obtained by conductive atomic
force microscopy reveal that the surfaces of the Zr–In2O3 films exhibit a distribution of coexisting conducting and nonconducting regions, and that the area of the nonconducting surface
increases with the oxygen content in the sputtering gas. The resistivity is minimized to 3.51×10−4 Ω cm when the Zr–In2O3 film is grown in an Ar atmosphere and the average transmittance in the visible light region is ∼85%. The optical band gap
decreases as the oxygen content in the sputtering gas increases. 相似文献
14.
Vasily Lavrentiev Jiri Vacik Hiroshi Naramoto Kazumasa Narumi 《Applied Physics A: Materials Science & Processing》2009,95(3):867-873
The structure transformation occurring in fullerene film under bombardment by 50 keV C60+ cluster ions is reported. The Raman spectra of the irradiated C60 films reveal a new peak rising at 1458 cm−1 with an increase in the ion fluence. This feature of the Raman spectra suggests linear polymerization of solid C60 induced by the cluster ion impacts. The aligned C60 polymeric chains composing about 5–10 fullerene molecules have been distinguished on the film surface after the high-fluence
irradiation using atomic force microscopy (AFM). The surface profiling analysis of the irradiated films has revealed pronounced
sputtering during the treatment. The obtained results indicate that the C60 polymerization occurs in a deep layer situated more than 40 nm below the film surface. The deep location of the C60 polymeric phase indirectly confirms the dominant role of shock waves in the detected C60 phase transformation. 相似文献
15.
A. D.?Rata A.?Herklotz L.?Schultz K.?D?rr 《The European Physical Journal B - Condensed Matter and Complex Systems》2010,76(2):215-219
We investigate the structure and magnetic properties of
thin films of the LaCoO3 compound. Thin films are deposited
by pulsed laser deposition on various substrates in order to tune
the strain from compressive to tensile. Single-phase (001)
oriented LaCoO3 layers were grown on all substrates despite
large misfits. The tetragonal distortion of the films covers a
wide range from -2% to 2.8%. Our LaCoO3 films are
ferromagnetic with Curie temperature around 85 K, contrary to the
bulk. The total magnetic moment is below 1μ
B
/Co3+, a
value relatively small for an exited spin-state of the Co3+
ions, but comparable to values reported in literature. A
correlation of strain states and magnetic moment of Co3+ ions
in LaCoO3 thin films is observed. 相似文献
16.
M. Belmeguenai S. Mercone C. Adamo T. Chauveau L. Méchin P. Monod P. Moch D. G. Schlom 《Journal of nanoparticle research》2011,13(11):5669-5675
Nearly 50-nm thick La0.7Sr0.3MnO3 (LSMO) films were grown on Si substrates using molecular beam epitaxy on (001) Si substrates over-layered by a 20 nm thick
SrTiO3 (STO) or by a 20 nm thick CaTiO3 (CTO) film. In addition, a reference LSMO film was directly deposited on a (001) STO substrate by pulsed laser deposition.
For all the samples, X-ray diffraction revealed an excellent epitaxy of the LSMO film and small mosaicity around (001), with
in-plane [100] and [010] cubic axes. The LSMO/CTO films are in-plane compressed while the LSMO/STO ones are in-plane extended.
The temperature dependence of their static magnetic properties was studied using a SQUID, showing a Curie temperature overpassing
315 K for all the samples. Hysteresis loops performed at room temperature (294 K) with the help of a vibrating sample magnetometer
(VSM) are also discussed. At 294 K Micro-strip ferromagnetic resonance (MS-FMR) was used to investigate the dynamic magnetic
properties. It allows concluding to a strong anisotropy perpendicular to the films and to a weak fourfold in-plane anisotropy
with easy axes along the [110] and [1[`1]0 1\bar{1}0 ] directions. Their values strongly depend on the studied sample and are presumably related to the strains suffered by the
films. 相似文献
17.
R. Moubah S. Colis C. Ulhaq-Bouillet G. Schmerber N. Viart M. Drillon A. Dinia D. Muller J. J. Grob 《The European Physical Journal B - Condensed Matter and Complex Systems》2008,66(3):315-319
Layered cobalt oxides Ca3Co4O9 thin films have been grown directly on c-cut sapphire substrates using pulsed laser deposition. X-ray diffraction and transmission
electron microscopy characterizations show that the deposited films present the expected monoclinic structure and a texture
along the direction perpendicular to the Al2O3(001) plane. The Ca3Co4O9 structure presents six variants in the film plane. Rutherford backscattering spectroscopy shows that the films are stoichiometric
and that the film thickness agrees with the nominal value. The susceptibility χ of the films, recorded along the c-axis of
the substrate, after field cooling and zero field cooling in an applied field of 1 kOe shows two magnetic transitions at 19
and 370 K which agree well with previous findings on single crystal samples. In turn, at low temperature (5 K), the magnetization
curve along the c-axis exhibits coercive field and remanent magnetization much smaller than those reported for bulk samples,
which can be related to the influence of structural variants and structural defects. 相似文献
18.
Thin films of CdSxTe1-x were deposited by the pulse electrodeposition technique using cadmium sulfate, sodium thiosulfate, and tellurium dioxide
on titanium and conducting glass substrates. Structural studies indicated the formation of polycrystalline films possessing
hexagonal structure. The resistivity varies from 53 Ω cm to 8 Ω cm as the stochiometric coefficient “x” value decreases from 1 to 0. The carrier concentration increases with CdTe concentration. It is observed that as the post-heat
treatment temperature increases, the photosensitivity also increases. It is observed that a post-heat treatment temperature
of 550 °C results in high photosensitivity as well as low light resistance. The optical constants, refractive index (n) and extinction coefficient (k) were evaluated from the transmission spectra of the films of different composition. 相似文献
19.
A. N. Veis 《Russian Physics Journal》2008,51(7):714-717
Spectra of optical absorption in Bi0.5Sb1.5Te3 films grown on mica and KBr substrates have been investigated for T = 145 and 300 K. The data obtained have been analyzed
together with the data of investigations on the fundamental absorption edge for Bi2Te3 available in the scientific literature. It has been revealed that the interband absorption spectra for both Bi0.5Sb1.5Te3 and Bi2Te3 represent a superposition of two components corresponding to direct and indirect allowed optical transitions. In this case,
the least energy gap separating the valence band and the conduction band is direct for Bi2−xSbxTe3 (x ≤ 1.5, T = 300 K). For Bi0.5Sb1.5Te3 the temperature variation rates have been estimated for the thresholds of direct and indirect interband transitions. It has
been shown that this solid solution is direct gap solution at T ≥ 145 K.
Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 7, pp. 50–52, July, 2008. 相似文献
20.
Lei Shi Jiang Yin Kuibo Yin Feng Gao Yidong Xia Zhiguo Liu 《Applied Physics A: Materials Science & Processing》2008,90(2):379-384
As potential gate dielectric materials, pseudobinary oxide (TiO2)x(Al2O3)1-x (0.1≤x≤0.6) films (TAO) were deposited on Si (100) substrates by pulsed-laser deposition method and studied systematically
via various measurements. By a special deposition process, including two separate steps, the TAO films were deposited in the
form of two layers. The first layer was deposited at room temperature and the second layer was completed at the substrate
temperature of 400 °C. Detailed data show that the properties of the TAO films are closely related to the ratio between TiO2 and Al2O3. The existence of the first layer deposited at room temperature can effectively restrain the formation of the interfacial
layer. And according to the results of X-ray photoelectron spectroscopy and high-resolution transmission electron microscopy
performed on the films, no other information belonging to the silicon oxide could be observed. For the (TiO2)0.4(Al2O3)0.6 film, the best result has been achieved among all samples and its dielectric constant is evaluated to be about 38. It is
valuable for the amorphous TAO film as one of the promising dielectric materials for high-k gate dielectric applications.
PACS 77.55.+f; 73.40.Qv; 81.15.Fg 相似文献